What are tumor markers?
Tumor markers are substances found in the blood, urine, or tissues of some people with cancer that are higher than normal. These substances, also known as biomarkers, can be produced by the tumor. These can also be produced by healthy cells in response to the tumor. Tumor marker tests check if your body has these substances and in what amounts. Tumor markers are usually proteins. Also, some genetic mutations are now being used as tumor markers.
Tumor markers are substances that cancer cells release into the blood or urine or substances created by the body in response to cancer cells. Tumor markers are used to assess how well a patient responds to treatment and to check for tumor recurrence. The role of tumor markers in the identification, diagnosis, and treatment of cancers is currently being investigated.
Tumor markers can be used to identify potential problems, but should be used in conjunction with other tests for the following reasons:
- People with benign conditions may also have levels of these substances in their blood
- Not all people with a tumor have tumor markers
- Some tumor markers are not specific to any type of tumor
Why do I need a tumor marker test?
If you are currently receiving cancer treatment, have completed cancer treatment, or are at high risk for cancer due to family history or other factors, you may need a tumor marker test.
The type of test you do depends on your health, your medical history, and the symptoms you have. The most common types of tumor markers and what they are used for.
Among other tests, tumor marker tests can help doctors diagnose cancer and recommend a treatment plan for a person. Why, when, and how often these tests are done can vary greatly from person to person. In rare cases, they are used to help detect a specific type of cancer in people at high risk for the disease before signs and symptoms appear. But doctors mainly use tumor marker tests:
- Determine what type of treatment or combination of treatments works best for a particular type of cancer
- Find out how well the treatment works
- Assess the person’s chances of recovery
- Find out how likely cancer will come back after treatment and if it occurs
Are there any risks to the test?
There is very little risk of having a blood test done. You may feel some pain or bruise at the injection site, but most symptoms clear up quickly.
There is no risk of a urine test.
If you have a biopsy, you may have small bruising or bleeding at the biopsy site. You may feel a bit uncomfortable on the site for a day or two.
How are tumor markers test used?
High levels of tumors are a sign of cancer. Among other things, tumor marker tests can help doctors diagnose specific types of cancer and plan treatment. Tumor marker tests are commonly used to do the following:
Find out if a person has cancer. High levels of tumor markers indicate a specific type of cancer. A tumor marker test may be used as part of your initial diagnosis.
Guide treatment decisions. Some tumor marker tests tell doctors whether to give chemotherapy or immunotherapy. Others help doctors choose which drugs work best.
Check the progress of the treatment. Changes in tumor marker levels show how well the treatment works.
Evaluate the possibility of recovery. Tumor markers can help doctors assess cancer behavior and response to treatment. They can also hamper your chances of recovery.
Either repeat or watch a replay. Recurrence occurs when cancer comes back after treatment. Tumor marker tests can help assess how far away you are. That is why these tests may be part of your care after treatment is finished. They help to find the recurrence more than other tests.
Tumor marker tests can also be used for cancer in people at high risk for the disease. Or you can have these tests to learn more about cancer when doctors first find it.
How are the tumor markers test done?
A member of your healthcare team will take a sample of your blood or urine. The sample is sent to the laboratory for analysis. Some tests need to be done more than once, as tumor marker levels can change regularly.
You may also need other cancer screening tests and treatment. Tumor marker results have limitations and are sometimes inaccurate. They may be:
- Show that the tumor is growing with or without it
- Show that there is no tumor when one is present, or show that treatment works when it is not
- Neither test is correct. Then your doctor will order a variety of tests to find the answers.
What happens during a tumor markers test?
There are several ways to test for tumor markers. Blood tests are the most common tumor marker tests. Urine tests or biopsies can also be used to look for tumor markers. A biopsy is a small procedure that removes a small piece of tissue for examination.
If you are having a blood test, a healthcare professional will take a sample of blood from a vein in your hand with a small needle. After the needle is inserted, a small amount of blood is collected in a test tube or vial. You may feel a slight sting when the needle goes in or out. This usually takes less than five minutes.
If you are having a urinalysis, ask your healthcare provider for instructions on how to provide your sample.
If you have a biopsy, the doctor will remove a small piece of tissue by cutting or scraping the skin. If your provider needs to examine tissue inside your body, he or she may use a special needle to remove the sample.
Limitations of tumor markers testing
The tumor marker tests are not correct. They are often not cancer-specific and may not be as sensitive to cancer recurrence. Tumor markers alone are not sufficient to identify a tumor. You may need other tests to learn more about cancer or recurrence. Here are some limitations to tumor marker testing.
Increases levels of tumor markers in a non-cancerous disease or condition.
People who do not have cancer have higher levels of tumor markers.
Tumor markers levels can change over time. The tests may not get the same result every time.
Tumor marker levels may not increase until the cancer is severe. It does not help in early detection or a high risk of cancer. It also does not help to find the recurrence.
Some cancers do not produce the tumor markers found in the blood. And some types of cancer do not have tumor markers.
Although your type of cancer generally produces tumor markers, your tumor marker levels may not increase.
What do the results mean?
Depending on the type of test you have and how it is used, your results may be:
- Help diagnose your type or stage of cancer
- Show if your cancer treatment is working
- Help plan future treatment
- Show that your cancer has come back after completing treatment
- If you have questions about your results, speak with your healthcare provider
Do I need to know more about tumor marker tests?
Tumor markers can be very helpful, but the information they provide may be limited because:
- Some non-cancerous conditions cause tumor markers
- Some people with cancer have no signs of a tumor
- There are no tumor markers in all types of cancer
- Therefore, tumor markers are always used in conjunction with other tests to help diagnose and monitor cancer